Investigation of Diffusion Kinetics by Auger Electron Spectroscopy

摘要

In this paper, we present a comparative experimental and theoretical mass transport analysis in model metal/metal structures (Ni/Cu and Ag/Cu thin layers) for systems without compound formation by Auger Electron spectroscopy. We show the conditions where grain-boundary and/or volume diffusion coefficients can be accurately determined at low temperatures by monitoring (i) the Ag surface segregation kinetics on nanocrystalline Cu films and (ii) the dissolution of ultrathin Ni deposits onto Cu (111) substrates. More generally, we establish that (i) for systems with low solubility, grain-boundary diffusion data (when nanocrystalline films are used) are obtained from the kinetics of the surface segregating element by the surface accumulation technique and (ii) for systems with total mutual solubility because of the competition between dissolution and surface segregation bulk diffusion can be obtained only if the diffusion of the deposit in the substrate is faster than that of the substrate in the deposit (diffusion asymmetry) and if the role of fast circuits can be excluded. It is also illustrated that in case (ii), if the diffusion asymmetry is large, the interface remains sharp and shifts linearly with time, i.e. the parabolic law is violated.